Loss of Brain Stem Cells
may cause Central Sleep Apnea

August 9th 2005

CPAP machine

Researchers at the University of
California at Los Angeles (UCLA) reported Monday that they believe that
people who die in their sleep may stop breathing because they have lost
too many brain cells. They tested Rats and determined that the loss of
key brain stem cells may halt autonomic functions such as breathing.

As we age we naturally lose these
brain stem cells. According to Jack Feldman, the principle investigator
and distinguished professor of neurobiology at the David Geffen School
of Medicine at UCLA "We wanted to reveal the mechanism behind central
sleep apnea, which most commonly affects people after age 65."

Professor Feldman continued "Unlike
obstructive sleep apnea — in which a person stops breathing when their
airway collapses — central sleep apnea is triggered by something going
awry in the brain's breathing center."

In previous research Feldman’s team
identified a region of the brain stem responsible for breathing they
dubbed preBotzinger complex (preBotC). They called this area the
“command post for generating breathing in mammals”, and identified a
small group of preBötC neurons responsible for issuing the commands.

This research studied the role of preBotC neurons
during sleep. They killed more than half of the preBotC neurons in a
number of adult rats. The results were dramatic after just a few nights
of study. The rats completely quit breathing during REM sleep which
forced "the rat to wake up in order to start breathing again," according
to Leanne McKay, postdoctoral fellow in neurobiology. "Over time, the
breathing lapses increased in severity, spreading into non-REM sleep and
eventually occurring when the rats were awake, as well."

Humans possess a few thousand of these specialized
preBotC cells, and they are slowly lost over a lifetime. "We speculate
that our brains can compensate for up to a 60 percent loss of preBötC
cells, but the cumulative deficit of these brain cells eventually
disrupts our breathing during sleep. There's no biological reason for
the body to maintain these cells beyond the average lifespan, and so
they do not replenish as we age," Feldman said. "As we lose them, we
grow more prone to central sleep apnea."

According to the UCLA team when elderly but otherwise
healthy people die during sleep, physicians commonly record the cause of
death as heart failure. Feldman believes that it is likely the deaths
occurred from central sleep apnea. The scientists suspect “central
sleep apnea also strikes people suffering the late stages of
neurodegenerative disorders, such as Parkinson's disease, Lou Gehrig's
disease and multiple system atrophy, all serious conditions that lead to
movement problems.”

Most people with sleep apnea don’t realize they have
sleep apnea. You are asleep and don’t realize you stop breathing.
During the day it is unlikely you stop breathing. When you sleep your
throat becomes relaxed and collapses (obstructive type apnea).

If you suspect you have sleep apnea a sleep study can
be done. Of the two types of apnea, obstructive is far more common. If
you snore there is a good chance you have obstructive sleep apnea.
Sleep apnea is a likely cause of various ailments including high blood
pressure in the early morning, a tired feeling during the day and a loss
of cognitive ability. As apneas occur blood pressure rises. It has
been speculated that this could cause strokes and heart attacks.

There are treatments for both sleep types of sleep
apnea. The most common treatment for
sleep apnea is a CPAP (constant positive air pressure) machine.
There is a special type of CPAP called a Bi-PAP that may help
individuals with central sleep apnea. These machines will almost always
stop the user from snoring (the wife will love it).

Talk to your doctor. Most insurance
companies cover the sleep study and CPAP machine. If you do not have
insurance ask for a discount from the specialists. The online edition
of Nature Neuroscience reported the findings on Aug. 7.